1. Field of the Invention
The present invention relates to a group communication system, a group ID number issuing apparatus, and a call control apparatus for providing a plurality of subscribers belonging to a predetermined group with a so-called group communication service performing intercommunication of the terminal devices.
2. Description of the Related Art
Recent years have seen considerable progress in an IP Multimedia Subsystem (IMS), which is a solution using an IP (Internet Protocol) network to provide communication services which have been provided through a conventional fixed-line phone, mobile communication, broadcasting, and the like (for example, see 3GPP TS23.228, IP Multimedia Subsystem (IMS)). The IMS allows a flexible call control to be performed on an voice call and a TV phone over the IP network.
Still alternatively, JP-A-2007-142903 (Abstract, paragraphs 0002-0004 etc.) has proposed a technique using an MCU (Multi Point control Unit) to build an optimal communication path for performing group communication, that is, a plurality of persons perform communication at the same time.
Conventionally, users intending to perform group communication have been used the above described MCU or a server to specify a communication partner to obtain a desired connection, or have been used a service in the form of using a special communication tool such as a PoC (Push talk over Cellular) standardized by OMA (Open Mobile Alliance).
It should be noted that the PoC is a service using the IP network to perform one-way communication and allows calling parties to be grouped. One party or a plurality of parties belonging to a group in calling state can be selected. When a call button is pressed, communication can be initiated.
In addition, in such a PoC communication, JP-A-2006-295897 (Abstract, paragraph 0021 etc.) proposes a technique which does not notify the other users of the user's own address depending on the user's setting.
Further, regarding the group communication, various proposals have been made to pursue convenience from diverse points of view.
For example, JP-A-2007-329582 (Abstract, paragraph 0012 etc.) proposes to reduce the workload of a user in forming a subgroup and the like for group communication to easily enable inter-subgroup communication.
JP-A-2007-329582 discloses that a group communication server stores subgroup information defining a subgroup in a group and timing information for establishing intercommunication connections of terminal devices belonging to the subgroup, as well as a control means is provided to control establishing connections among terminal devices belonging to the subgroup at the timing based on the timing information.
The connections among terminal devices are controlled based on subgroup information complied as a database to eliminate the need for a user to form a subgroup, change a terminal belonging to the subgroup, and other operations. Therefore, it is proposed to be possible to reduce the workload of the user in forming a subgroup and the like and to easily provide an inter-subgroup communication.
Still alternatively, JP-A-2007-221592 (Abstract, paragraph 0001 etc.) proposes a group communication system so as to enable a communication within the same group in such a manner that each user exchanges a temporary number with each other without knowing the other party's basic contract number.
Still alternatively, JP-A-2005-38276 (Abstract, paragraph 0028 etc.) proposes to use a random number, a time of day, a user ID, and the like to issue a group ID and a password so as to issue a pair of a group ID and a passcode corresponding to this, which is not overlapped with one issued to the other registered groups when group communication is performed.
However, the group communication based on a method via the above described MCU and the like unfortunately lacks convenience since an originator specifies the phone numbers of all the group members and then makes a call, while later in order to perform a group intercommunication of the same members, the originator needs to specify the phone numbers of all the group members again from the very beginning in the same manner as before.
As a method for improving this point, it can be considered to make a call from a group phone book preliminarily registered by a group member. However, this method imposes a workload on the originator to access a server providing the service and then make a call.
The above described proposals in the patent documents have not reached the point of providing the user with convenience in that a group organization tailored to the original intention of a subscriber (user) wanting to perform a group communication is allowed, while the system side issues a representative number to the group, and after the issuance, the user can use the issued representative number to perform a group communication in substantially the same manner as in communicating with a single partner (subscriber).
In view of the above points, the present invention has been made, and an object of the present invention is to provide a group communication system, a group ID number issuing apparatus, and a call control apparatus capable of fully reflecting the intention of the user to a group communication in which a plurality of users perform communications at the same time, and after a group is organized based on the intention of the user, allowing the user to perform the group communication in simple operation in the same manner as an ordinary call.